Quick answer
Electric Grid The electric grid is the connected network of power plants, high-voltage transmission lines, substations, transformers and local distribution lines that carries electricity from where it is generated to the homes and businesses that use it.
A grid-tied solar home sits at the very end of that network: it draws power from the grid when the panels fall short and sends surplus back through the same meter.
Quick facts
The key facts about electric grid, with sources:
- Three parts
- Generation, transmission, distribution 1
- US regions
- Eastern Interconnection, Western Interconnection, ERCOT (most of Texas) 1
- Who keeps it balanced
- Balancing authorities match supply to demand second by second 1
- Energy lost on the way
- About 5% in transmission and distribution, 2018–2022 average 3
- US utility-scale generation, 2025
- About 4.43 trillion kWh; natural gas 41%, renewables 24%, nuclear 18%, coal 17% 2
- Average outage time, 2024
- About 11 hours per customer; 80% from major events 4
- Where a home connects
- The distribution system, at the utility meter
Key takeaways
- The grid is the network that carries power from plants to your meter.
- It has three stages: generation, transmission (long distance) and distribution (local).
- Supply must match demand every second, because the grid stores very little.
- A grid-tied solar home both buys from and sends power to the local lines.
- In a blackout, grid-tied solar shuts off unless you have a battery.
- South Carolina had the longest average outages of any state in 2024, the EIA says.
How the grid moves power
Power plants make electricity. Transformers at the plant step it up to very high voltage, because high voltage loses less energy over long distances. Transmission lines carry it across a region to substations. There, transformers step it back down for the local distribution lines that run along streets.
A final transformer on a pole or a pad near your house drops it to the 120/240 volts your panel uses. Voltage is electrical pressure; the lower level is safer inside homes.
The EIA describes the result as thousands of miles of high-voltage lines and millions of miles of low-voltage lines, linking thousands of power plants to hundreds of millions of customers. In the early 1900s there were more than 4,000 separate local utilities. They were linked together mostly after World War II.
Sources: [1]
From power plant to your outlet, and back
- Power plant → step-up transformer → transmission line → substation → distribution line → neighborhood transformer → utility meter → your electrical panel
- Rooftop solar → inverter → your panel → home loads first → surplus out through the meter to the distribution line
How the grid stays balanced
There is almost no storage in the chain, so supply has to match demand at every moment. Balancing authorities do that matching. They dispatch plants up and down as load changes.
Inverters now help too. The DOE says smart inverters can talk with the utility and adjust output to help hold the grid’s frequency steady. Some advanced inverters can even help restart a grid after a blackout, which is called black start.
The three US interconnections
The three stages of the grid
| Stage | What it does | What you see |
|---|---|---|
| Generation | Power plants and large solar or wind farms make electricity | Plants, solar farms, wind turbines |
| Transmission | High-voltage lines move power long distances | Tall steel towers and big substations |
| Distribution | Lower-voltage lines deliver power to streets and homes | Wooden poles, pad-mounted boxes, your meter |
Example: one day of a solar home’s trade with the grid
The kWh numbers below are made up to show the logic. Real numbers depend on your system, weather and use.
| Time | Solar | Home use | Grid |
|---|---|---|---|
| 6 a.m. | 0 kWh | 1 kWh | Buys 1 kWh from the grid |
| Noon | 5 kWh | 2 kWh | Sends 3 kWh to the grid |
| 6 p.m. | 1 kWh | 3 kWh | Buys 2 kWh from the grid |
| Day total | 6 kWh | 6 kWh | Bought 3, sent 3 |
Even when solar matches your daily use, you still lean on the grid at night. How your utility credits the 3 kWh you sent decides how much you save. See export compensation.
Where the grid’s power comes from
The EIA says US utility-scale plants made about 4.43 trillion kWh in 2025. Natural gas made 41%, renewables 24%, nuclear 18% and coal 17%. Solar was about 7% of the total, and wind about 11%.
Small-scale solar, mostly rooftops, made about 0.09 trillion kWh on top of that. That is the part of the grid homeowners own. Our solar statistics page tracks it by state.
Sources: [2]
What the grid does for a solar home
- Fills the gaps. At night and on cloudy days the house runs on grid power, so the system does not have to be sized for the worst day of the year.
- Takes the surplus. Midday output the house cannot use flows onto the distribution line, and the utility credits it under its export rule.
- Sets the safety rules. A grid-tied inverter must shut off when the grid goes down so it cannot energize lines that crews are repairing.
- Needs permission first. The utility approves each connection through interconnection, which ends in permission to operate.
Sources: [6]
Limits of the grid
Outages happen. The EIA says the average US customer had about 11 hours without power in 2024, nearly twice the yearly average of the decade before. Hurricanes Beryl, Helene and Milton caused 80% of those hours. Outages not tied to major events average about 2 hours a year.
Some power is lost on the way. The EIA says transmission and distribution losses averaged about 5% from 2018 to 2022. Power made on your roof and used in your home skips that trip.
Local lines have limits. On some streets, a lot of rooftop solar can push the line near its limits, so the utility may study or limit new connections.
How the grid shows up in your costs
Your bill pays for the grid in two ways. Energy charges, per kWh, cover making the power. Fixed and delivery charges cover poles, wires, meters and service. Solar cuts the first much more than the second. See electricity rates.
Staying connected is usually cheaper than going off-grid, because you avoid buying batteries big enough for several cloudy days. The trade-off is that you keep paying fixed monthly charges. Our solar cost guide covers the rest.
How a solar home joins the grid
Your installer handles this. The usual steps:
- The installer sends an interconnection application to your utility.
- The utility reviews it, and may study the local line for larger systems.
- The system is installed and passes a local inspection.
- The utility installs or programs a two-way meter.
- The utility grants permission to operate, and you switch on.
Who maintains which part
The utility maintains the lines, transformers and meter. You maintain everything on your side of the meter, including the solar system and your electrical panel.
If a line is down or your whole street is dark, call the utility. If only your solar is off while the grid is fine, call your installer.
Warning signs and when to call
Call the utility or a licensed electrician if:
- A power line is down or sparking. Stay far away and call the utility or 911.
- Lights dim or flicker often, which can mean a grid or wiring problem.
- Your inverter shows repeated grid voltage or frequency errors.
- Half the house has power and half does not.
Safety rule
Treat every downed line as live. Never connect a generator or solar to house wiring without a transfer switch installed by a licensed electrician; backfeed can kill line workers.
Who regulates the grid
State level. State utility commissions set retail rates and approve export rules for investor-owned utilities. Co-ops and city utilities often set their own, through their boards.
Nationally, investor-owned utilities served about 72% of customers in the EIA’s 2017 count 7. Santee Cooper’s rates, for example, are set by its board, not the SC Public Service Commission 9.
Regional level. Balancing authorities run day-to-day operations so supply and demand match.
Connection standard. IEEE 1547-2018 sets how distributed energy resources, such as rooftop solar, connect to the grid. Utilities build it into their interconnection rules.
Grid vs utility vs microgrid
| Term | What it is | Glossary |
|---|---|---|
| Electric grid | The physical network of plants, lines and transformers | This page |
| Utility | The company or agency that serves and bills you | See related terms below |
| Distributed energy resource | Small power sources on the grid edge, like rooftop solar | DER |
| Off-grid system | A home with no grid connection at all | Off-grid vs grid-tied |
Common misconceptions
- Myth Solar panels keep my lights on in a blackout.
- Reality A standard grid-tied system shuts down with the grid by design. Backup needs a battery or another source and equipment that isolates the house.
- Myth My exported solar powers the whole grid.
- Reality Exported power is used by the nearest loads on your distribution line, usually your neighbors.
- Myth Going off-grid is the same as having solar.
- Reality Off-grid means no utility connection at all, which needs much more storage. Most home systems stay connected.
- Myth The grid stores extra power for me.
- Reality The grid stores almost nothing. Your utility credits exports on paper; the power is used right away.
The grid in SC, GA and VA
All three states sit on the Eastern Interconnection 1. South Carolina customers had longer outages than any other state in 2024, nearly 53 hours on average, the EIA says 4.
SC homes are served by investor-owned companies such as Duke Energy Carolinas and Dominion Energy South Carolina, the state-owned Santee Cooper, co-ops such as Berkeley Electric, and city systems such as Greer CPW and Rock Hill.
In Virginia, net metering rules differ for investor-owned utilities and co-ops under Va. Code §56-594 and §56-594.01 10.
What the grid means for your solar decision
Think about the grid when you decide:
- Battery or not: frequent, long outages favor adding storage.
- System size: utility caps and export pay set the sweet spot.
- Rate plan: time-of-use rates change when your solar is worth most.
- Off-grid or not: only worth it where grid power is far away or very costly to bring in.
Related guides
Questions about electric grid
Who owns the electric grid?
No single owner. Lines belong to investor-owned utilities, cooperatives, public power agencies and transmission companies. Regional operators and balancing authorities coordinate how it runs. Your local utility owns the lines and meter that serve your home.
Does solar power go back into the grid?
Yes, on a grid-tied system. Whatever the house does not use at that moment flows out through the meter. The utility credits it under its net metering, net billing or buyback rule. The power is used by nearby homes right away.
Why does grid-tied solar shut off during a power outage?
Inverters are required to stop exporting when the grid fails, so they do not energize lines that utility crews are working on. A battery with the right transfer equipment can keep selected circuits running.
Is it cheaper to stay on the grid with solar?
For most homes, yes. Staying connected avoids buying enough batteries to cover several cloudy days. The cost is the utility’s fixed monthly charges. Off-grid makes sense mainly where bringing in power lines would be very costly.
How much power is lost on the grid?
About 5%. The EIA says transmission and distribution losses averaged about 5% of the electricity moved in the US from 2018 to 2022. Most loss is heat in lines and transformers.
How often does the power go out in the US?
The EIA says the average customer had about 11 hours of interruptions in 2024, nearly double the prior decade’s average. Major storms caused 80% of that time. Outages not tied to major events average about 2 hours a year.
What are the three US power grids?
The Eastern Interconnection, the Western Interconnection and ERCOT, which covers most of Texas. Each runs mostly on its own, with only limited links between them. South Carolina, Georgia and Virginia are on the Eastern Interconnection.
What powers the US grid?
In 2025, natural gas made 41% of US utility-scale electricity, renewables 24%, nuclear 18% and coal 17%, the EIA says. Solar made about 7% and wind about 11%. Rooftop solar adds more on top of those figures.
Can rooftop solar help the grid?
Yes. It makes power close to where it is used, which avoids line losses. Smart inverters can also help steady the grid’s voltage and frequency, the DOE says. Too much on one street can strain local lines, so utilities review each connection.
Sources
- US EIA, Electricity explained: How electricity is delivered to consumers, retrieved .
- US EIA, Electricity explained: Electricity in the United States, retrieved .
- US EIA, FAQ: How much electricity is lost in transmission and distribution?, retrieved .
- US EIA, Today in Energy: Hurricanes in 2024 led to the most hours without power in 10 years (1 Dec 2025), retrieved .
- US DOE Solar Energy Technologies Office, Solar Integration: Inverters and Grid Services Basics, retrieved .
- US DOE Solar Energy Technologies Office, Homeowner’s Guide to Going Solar, retrieved .
- US EIA, Today in Energy: Investor-owned utilities served 72% of US electricity customers in 2017, retrieved .
- IEEE, Standard 1547-2018 for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces, retrieved .
- Santee Cooper, 2025 rate study: solar, retrieved .
- Code of Virginia §56-594 (net energy metering), retrieved .
Expert review
Written by the HyreSolar Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Grid structure, interconnections, generation mix, line losses and outage hours are from the EIA pages cited, read on the retrieval date. Inverter grid services are from the DOE.
South Carolina utility names and Santee Cooper governance come from the verified sc-local facts file; Virginia from the verified statute rows. The daily example uses made-up kWh to show the logic.
Suggest a correction. We fix errors and say what changed.